System for improving the usage of a thermoelectric cooler in a downhole tool

ABSTRACT

A downhole tool comprises a chassis for supporting printed circuit boards having electrical components mounted thereon. The downhole tool comprises at least one thermoelectric cooler, such as a Peltier cooler, for cooling particular electrical components. The downhole tool also comprises a heat pump that may be used for maintaining the temperature of the hot side of the thermoelectric cooler to a sufficiently low temperature so that the thermoelectric cooler works efficiently. The heat pump may further be used for providing additional cooling in the downhole tool.

CROSS-REFERENCE TO RELATED APPLICATIONS

None

BACKGROUND

This disclosure relates generally to methods and apparatus for activelycooling downhole electronics or other components contained within adownhole tool. More particularly, this disclosure relates to systems forimproving the usage of a thermoelectric cooler in a downhole tool. Forexample, this disclosure relates to systems for improving the usage of aPeltier cooler in a logging tool used for oil and gas exploration orproduction.

Peltier coolers are active heat pumps which transfer heat between a coolside and a hot side upon supply and consumption of electric energy.Peltier coolers have a cooling power per unit of surface area that isusually smaller than other heat pumps. The temperature differentialbetween the hot side and the cool side at which Peltier coolers operateefficiently is limited, typically to approximately 70 degrees C. Thecool side and the hot side of Peltier coolers are normally locatedadjacent to each other, which limits the distance over which Peltiercoolers can transfer heat.

Nevertheless, Peltier coolers can be advantageous for use in a downholetool because these coolers do not have moving parts or a circulatingfluid. For example, Peltier coolers may be used for providing localthermal regulation of relatively small downhole tool components thatneed to be maintained within a specific temperature range to operateproperly.

When the temperature differential between the wellbore and the downholetool component to be cooled is large, Peltier coolers may becomeunsuitable because of their inefficiency. For example, Peltier coolersmay not be usable to transfer heat from a downhole tool component thatis at a temperature of 80 degrees C. to a wellbore environment that isat a temperature of 150 degrees C. or above.

When Peltier coolers are used for transferring heat from the inside of aDewar flask to the outside of the Dewar flask, the position of thePeltier cooler is typically constrained to the space leading to theopening of the Dewar flask. This constrained location of the Peltiercooler may make the cooling of components located deep inside the flaskproblematic. This constrained location of the Peltier cooler alsoimposes limits on the area of the cooler and, in turn, on its coolingpower. For example, in a downhole tool, Peltier coolers may typicallyhave an area that limits their cooling power to approximately 15 Watts.Thus, Peltier coolers may not be usable to cool a plurality ofcomponents located along a Dewar flask.

Accordingly, there is a continuing need in the art for methods andapparatus for improving the usage of thermoelectric coolers, such asPeltier coolers, in a downhole tool.

BRIEF SUMMARY OF THE DISCLOSURE

The disclosure describes an apparatus for use in a downhole tool thatcomprises at least one thermoelectric cooler. The thermoelectric coolermay be adapted for thermal coupling to a component mounted on a chassisof the downhole tool. The apparatus further comprises a heat pumpadapted for disposal into an elongated pressure housing of the downholetool. The heat pump includes a conduit that is filled with a coolingfluid. The heat pump may include a compressor or a loudspeaker capableof varying a cooling fluid pressure. In some embodiments, the heat pumpincludes a compressor and an expansion valve. The thermoelectric coolerincludes a cold side and a hot side. The hot side of the thermoelectriccooler is thermally coupled to a portion of the conduit.

The apparatus may further comprise one or more thermally insulatinghousings. Each thermally insulating housing includes at least oneopening. A thermally insulating housing may include one or morecompartments. The apparatus may further comprise at least one thermallyinsulating support. The thermally insulating support may be insertedinto the opening of the thermally insulating housing. The thermoelectriccooler may be partially embedded within the thermally insulatingsupport. The cold side of the thermoelectric cooler may be locatedinside the thermally insulating housing.

The apparatus may further comprise a heat exchanger. The heat exchangercontacts the hot side of the thermoelectric cooler. The heat exchangerincludes a passageway for the cooling fluid. The apparatus may furthercomprise a thermal conductor. The thermal conductor contacts the coldside of the thermoelectric cooler. The heat exchanger and/or the thermalconductor may be partially embedded within a thermally insulatingsupport.

In some embodiments, the apparatus comprises at least first and secondthermoelectric coolers. The hot side of the first thermoelectric coolermay be thermally coupled to a first portion of the conduit. The hot sideof the second thermoelectric cooler may be thermally coupled to a secondportion of the conduit. Either or both of the first and secondthermoelectric coolers may be partially embedded within a thermallyinsulating support that may be inserted into an opening of a thermallyinsulating housing. The cold side of either or both of the first andsecond thermoelectric coolers may be located inside the same compartmentof one thermally insulating housing, inside different compartments ofone thermally insulating housing, or inside different thermallyinsulating housings.

In some embodiments, the conduit may comprise first and second portions.The hot side of the thermoelectric cooler may be thermally coupled tothe first portion of the conduit. The cold side of the thermoelectriccooler may be located inside one compartment of one thermally insulatinghousing. The second portion may be located inside another compartment ofthe thermally insulating housing or inside another thermally insulatinghousing.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more detailed description of the embodiments of the disclosure,reference will now be made to the accompanying drawings, wherein:

FIG. 1 is a sectional view of a downhole tool including a thermoelectriccooler and a heat pump for improving the usage of the thermoelectriccooler, the heat pump involving a Vapor Compression Cycle;

FIG. 2 is a sectional view of a downhole tool including twothermoelectric coolers and a heat pump for improving the usage of thetwo thermoelectric coolers;

FIG. 2A is a sectional view of another downhole tool including twothermoelectric coolers and a heat pump, wherein the two thermoelectriccoolers are located inside different compartments of one thermallyinsulating housing, or inside different thermally insulating housings;

FIG. 3 is a sectional view of a downhole tool including a thermoelectriccooler and a heat pump for improving the usage of the thermoelectriccooler and for providing additional cooling in the downhole tool; and

FIG. 4 is a sectional view of a downhole tool including a thermoelectriccooler and a heat pump for improving the usage of the thermoelectriccooler, the heat pump involving an alternative to involving a VaporCompression Cycle.

DETAILED DESCRIPTION

It is to be understood that the following disclosure describes severalexemplary embodiments for implementing different features, structures,or functions of the invention. Exemplary embodiments of elements,arrangements, and configurations are described below to simplify thedisclosure; however, these exemplary embodiments are provided merely asexamples and are not intended to limit the scope of the invention.Additionally, the disclosure may repeat reference numerals and/orletters in the various exemplary embodiments and across the Figuresprovided herein. This repetition is for the purpose of simplicity andclarity and does not in itself dictate a relationship between thevarious exemplary embodiments and/or configurations discussed in thevarious Figures. Finally, the exemplary embodiments presented below maybe combined in any combination of ways, i.e., any element from oneexemplary embodiment may be used in any other exemplary embodiment,without departing from the scope of the disclosure.

All numerical values in this disclosure may be approximate values unlessotherwise specifically stated. Accordingly, various embodiments of thedisclosure may deviate from the numbers, values, and ranges disclosedherein without departing from the intended scope. Moreover, theformation of a first feature over or on a second feature in thedescription that follows may include embodiments in which the first andsecond features are formed in direct contact, and may also includeembodiments in which additional features may be formed interposing thefirst and second features, such that the first and second features maynot be in direct contact.

Certain terms are used throughout the following description and claimsto refer to particular elements. As one skilled in the art willappreciate, various entities may refer to the same element by differentnames, and as such, the naming convention for the elements describedherein is not intended to limit the scope of the invention, unlessotherwise specifically defined herein. Further, the naming conventionused herein is not intended to distinguish between elements that differin name but not function.

Referring initially to FIG. 1, a downhole tool, such as a logging toolused in oil and gas exploration or production, is illustrated inaccordance with some embodiments. The downhole tool comprises anelongated pressure housing 10 that is conveyed in a wellbore drilledinto the earth.

The downhole tool comprises a chassis 34 for supporting printed circuitboards 36 having electrical components 38 mounted thereon. Some of thesecomponents, such as a high precision clock, a gyroscope, or a particledetector, may benefit from being maintained at a relatively constanttemperature, for example, between 80 degrees C. and 100 degrees C. Othercomponents, such as certain electronics circuits, may only need to becooled when their temperature reaches their rating temperature, forexample, 150 degrees C.

In some cases, the wellbore environment in some locations along thewellbore may exceed 80 degrees C., and even 150 degrees C. For delayingthe heating of the electrical components 38 by the wellbore environment,the chassis 34, including the printed circuit boards 36 and theelectrical components 38, may be disposed within a thermally insulatinghousing 26. The thermally insulating housing 26 comprises a thermalinsulator 28. For example, the thermally insulating housing 26 may be aDewar flask having a vacuum chamber therein as an insulator. Thethermally insulating housing 26 includes at least one opening and atleast one thermally insulating support 30 that may be inserted into theat least one opening. Each thermally insulating support 30 may contactthe inner wall of the elongated pressure housing 10 for securing thethermally insulating housing 26 in the downhole tool. Also, eachthermally insulating support 30 may contact an end of the chassis 34 forsecuring the chassis 34 within the thermally insulating housing 26. Aplurality of feed-thru passages 32 may be provided across each thermallyinsulating support 30 for running electrical wires, and/or hydrauliclines in the downhole tool. In some alternative embodiments, thethermally insulating housing 26 may include only one opening. Anotherthermally insulating support may surround the thermally insulatinghousing 26 for further securing the thermally insulating housing 26 inthe downhole tool.

For transferring heat from at least some of the electrical components 38and/or for maintaining the temperature of at least some of theelectrical components 38, the downhole tool further comprises athermoelectric cooler 12, such as a Peltier cooler. Examples ofelectrical components 38 that may benefit from temperature regulationwith the thermoelectric cooler 12 include, but are not restricted to,high precision clocks, gyroscopes, or particle detectors.

The thermoelectric cooler 12 includes a cold side 16 and a hot side 14.The cold side 16 may be directly or indirectly thermally coupled to thecomponent to be cooled. For example, a thermal conductor 42 may contactthe cold side 16 of the thermoelectric cooler 12. The thermal conductor42 may, in turn, contact the chassis 34 on which the electricalcomponents 38 are mounted. Alternatively, the thermal conductor 42 maydirectly contact the electrical components 38, or may even by omitted byhaving the cold side 16 contacting the electrical components 38. Invarious embodiments, the thermal conductor 42 may include a heat pipe,or a material having a large thermal conductivity, such as aluminum. Thethermal conductor 42 may be partially embedded within the thermallyinsulating support 30.

As shown, the thermoelectric cooler 12 may be disposed perpendicularlyto the longitudinal axis of the elongated pressure housing 10. However,for increasing the area and thus the cooling power of the thermoelectriccooler 12, it can alternatively be disposed tilted relative to thelongitudinal axis of the elongated pressure housing 10. Further, thethermoelectric cooler 12 may be partially embedded within the thermallyinsulating support 30. For reducing the leakage of heat toward the coldside 16 of the thermoelectric cooler 12 and the component to be cooled,the cold side 16 may preferably be located inside the thermallyinsulating housing 26. The hot side 14 may be located outside thethermally insulating housing 26 to avoid or minimize leakage of heatfrom the hot side 14 inside the thermally insulating housing 26.

The thermoelectric cooler 12 transfers heat between the cold side 16 andthe hot side 14. As such, the temperature of the cold side 16 may belower than the temperature of the hot side 14 by an amount controllableby the electric power supplied to the thermoelectric cooler 12. However,that amount may be limited to approximately 70 degrees C. For example,the temperature of the cold side 16 may be in the range between 80degrees C. and 100 degrees C. The temperature of the hot side 14 maythus be limited to a maximum temperature of 150 degrees C. In caseswhere the wellbore environment is at a temperature sufficiently below(e.g., 20 degrees C. below) the temperature of the hot side 14, the heattransferred by the thermoelectric cooler 12 may passively dissipate fromthe hot side 14 into the wellbore environment.

In cases where the temperature of the wellbore environment is notsufficiently low, for example in wellbores that have an environment at atemperature of 150 degrees C. or above, the heat transferred by thethermoelectric cooler 12 may not passively dissipate in the environment,the temperature of the hot side 14 may thus increase over time, and theefficiency of the thermoelectric cooler 12 may consequently decreaseuntil the cooler is no longer capable of transferring heat from the coldside 16 to the hot side 14. For evacuating the heat transferred by thethermoelectric cooler 12 even in such hot environments, the downholetool comprises a heat pump 18. The heat pump 18 is adapted for beingdisposed within the elongated pressure housing 10 of the downhole tool.The heat pump 18 may be used for maintaining the temperature of the hotside 14 to a sufficiently low temperature so that the thermoelectriccooler 12 works efficiently. The heat pump 18 actively transfers heatfrom the hot side 14 of the thermoelectric cooler 12 to the wellboreenvironment, even when the wellbore environment is at a temperaturehigher than the temperature of the hot side 14. For example, thewellbore environment may be at a temperature of 200 degrees C., and theheat pump 18 may be capable of maintaining the temperature of the hotside 14 of the thermoelectric cooler 12 below 150 degrees C.

The heat pump 18 includes a conduit that is filled with a cooling fluid.The heat pump 18 provides active cooling of the cooling fluid. That is,upon supply of energy (e.g., mechanical energy provided by a motor), theheat pump 18 transfers heat from the cooling fluid into the wellboreenvironment.

Preferably, the heat pump 18 may be based on a Vapor Compression Cycle.As such, the heat pump 18 may include a compressor 22 and an expansionvalve 20, capable of varying a cooling fluid pressure. Hot vaporizedcooling fluid (e.g., steam) entering the heat pump 18 may be compressedby the compressor 22 into a condenser (not shown). In the condenser, thecooling fluid may condense (e.g., into water) and heat may dissipateinto the wellbore environment. The cooling fluid may then pass throughthe expansion valve 20. During expansion, the cooling fluid partiallyvaporizes and cools. Cold, partially liquid cooling fluid may then leavethe heat pump 18. Alternatively, the heat pump 18 may comprise aStirling engine or be based on thermodynamic cycles other than the VaporCompression Cycle.

The cooling fluid filling the conduit is used for cooling the hot side14 of the thermoelectric cooler 12. Accordingly, the hot side 14 of thethermoelectric cooler 12 is thermally coupled to a portion 24 of theconduit. For example, the downhole tool may further comprise a heatexchanger 40. The heat exchanger 40 contacts the hot side 14 of thethermoelectric cooler 12 and the heat exchanger 40 includes a passagewayfor the cooling fluid. The heat exchanger 40 may be partially embeddedwithin the thermally insulating support 30. In some embodiments, theheat exchanger 40 may include a heat pipe. In alternative embodiments,the heat exchanger 40 may be omitted and the cooling fluid filling theconduit may be directly in contact with the hot side 14 of thethermoelectric cooler 12.

Using a combination of a thermoelectric cooler with a heat pump based ona Vapor Compression Cycle or another thermodynamic cycle may beadvantageous over cascading several thermoelectric coolers. For example,cascading several thermoelectric coolers to maintain a large temperaturedifference between a downhole component and the wellbore environmenttypically leads to a lower efficiency than the combination of a singlethermoelectric cooler with a heat pump. Further, using a combination ofa thermoelectric cooler with a heat pump based on a Vapor CompressionCycle may be advantageous over using only a heat pump. Indeed, thecooling fluid selected for use in the Vapor Compression Cycle may beefficient to only cool a downhole component over a certain temperaturerange that depends on the phase transition temperature(s) of the coolingfluid. Combining a thermoelectric cooler with the heat pump may increasethe temperature range at which a downhole component may be cooled with aparticular cooling fluid.

Turning to FIG. 2, another downhole tool is illustrated in accordancewith some embodiments in which the downhole tool may comprise at least afirst thermoelectric cooler 12 a and a second thermoelectric cooler 12b. In some embodiments, the configuration of FIG. 2 may be used when aplurality of components located along the downhole tool (e.g., along athermally insulating housing 26) are to be cooled. Preferably, theconfiguration of FIG. 2 may be used when the downhole components cooledby the first thermoelectric cooler 12 a are maintained at a temperatureequal or sufficiently close to the temperature at which the downholecomponents cooled by the second thermoelectric cooler 12 b aremaintained. The configuration of FIG. 2 may also provide an increasedcombined area of the first thermoelectric cooler 12 a and the secondthermoelectric cooler 12 b, and thus an increased cooling power, whileavoiding or minimizing leakage of heat from the hot sides of the firstthermoelectric cooler 12 a and the second thermoelectric cooler 12 binside a thermally insulating housing 26.

The hot side 14 a of the first thermoelectric cooler 12 a may bethermally coupled to a first portion 24 a of the conduit. The hot side14 b of the second thermoelectric cooler 12 b may be thermally coupledto a second portion 24 b of the conduit. In some embodiments, the firstportion 24 a and the second portion 24 b of the conduit may be assembledin series. Accordingly, cooling fluid leaving the heat pump 18 may firstcirculate through the first portion 24 a, then circulate through thesecond portion 24 b before entering the heat pump 18. In otherembodiments, the first portion 24 a and the second portion 24 b of theconduit may be assembled in parallel. Accordingly, the flow of coolingfluid leaving the heat pump 18 may be split into a first stream ofcooling fluid that circulates through the first portion 24 a, and asecond stream of cooling fluid that circulates through the secondportion 24 b. The first and second streams may then rejoin and enter theheat pump 18.

When the first portion 24 a and the second portion 24 b of the conduitare assembled in series as explained hereinabove, the cooling of the hotside 14 a of the first thermoelectric cooler 12 a may be more efficientthan the cooling of the hot side 14 b of the second thermoelectriccooler 12 b because the cooling fluid may have vaporized and/or heatedat the hot side 14 a before reaching the hot side 14 b. Accordingly, thesecond thermoelectric cooler 12 b may be used for cooling componentsthat produce more heat than the components cooled by the firstthermoelectric cooler 12 a.

Either or both of the first thermoelectric cooler 12 a and secondthermoelectric cooler 12 b may be partially embedded within a thermallyinsulating support 30 that may be inserted into opposite openings of athermally insulating housing 26. The cold side 16 a or 16 b of either orboth of the thermoelectric coolers may be located inside the thermallyinsulating housing 26.

Turning to FIG. 2A, another downhole tool is illustrated in accordancewith some embodiments in which the thermally insulating housing 26 mayinclude a first compartment 101 and a second compartment 102. Incontrast with the configuration shown in FIG. 2, the configuration ofFIG. 2A may preferably be used when the downhole components cooled bythe first thermoelectric cooler 12 a are maintained at a temperaturedifferent from the temperature at which the downhole components cooledby the second thermoelectric cooler 12 b are maintained. In thisexample, the first compartment 101 and the second compartment 102 mayeach include only one opening. One thermally insulating support 30,provided with one or more feed-thru passages 32, may be inserted intoeach of the openings. The cold side 16 a of the thermoelectric cooler 12a may be located inside the first compartment 101. The cold side 16 b ofthe thermoelectric cooler 12 b may be located inside the secondcompartment 102. In alternative embodiments, a downhole tool maycomprise more than one thermally insulating housing 26, in a way similarto the downhole tool illustrated in FIG. 2A.

Turning to FIG. 3, another downhole tool is illustrated in accordancewith some embodiments in which the downhole tool may comprise a conduithaving a first portion 24 a and a second portion 24 b. The hot side 14of the thermoelectric cooler 12 may be thermally coupled to the firstportion 24 a of the conduit. The second portion 24 b may be locatedinside the thermally insulating housing 26. The second portion 24 b maybe used for providing additional cooling to electrical components 38that are too far from the cold side 16 of the thermoelectric cooler 12to be sufficiently cooled by the thermoelectric cooler 12. For example,the thermoelectric cooler 12 may be used for maintaining a particulardownhole tool components, such as a high precision clock, a gyroscope,or a particle detector, at a relatively constant temperature, forexample, between 80 degrees C. and 100 degrees C. The second portion 24b of the conduit may be used for cooling other components, such ascertain electronics circuits, only such that their temperature does notexceed their rating temperature, for example, 150 degrees C. Again,because of the difference of temperatures at which the downholecomponents are maintained, the cold side 16 of the thermoelectric cooler12 may preferably be located inside one compartment (i.e., thecompartment 101) of one thermally insulating housing. The second portion24 b may preferably be located inside another compartment (i.e., thecompartment 102) of the thermally insulating housing 26 or insideanother thermally insulating housing.

The first portion 24 a and the second portion 24 b of the conduit may beassembled in series or in parallel, as explained hereinabove withrespect to FIG. 2. When the first portion 24 a and the second portion 24b are assembled in series, consideration may be given to whether thecooling fluid circulates first through the first portion 24 a or thesecond portion 24 b. Having the cooling fluid circulate first throughthe first portion 24 a may further reduce the temperature of the hotside 14 of the thermoelectric cooler 12, and thus, may improve theefficiency of the thermoelectric cooler 12. Having the cooling fluidcirculate first through the second portion 24 b may reduce the amount ofheat leaked from the cooling fluid inside the thermally insulatinghousing 26.

Turning to FIG. 4, another downhole tool is illustrated in accordancewith some embodiments in which the heat pump 18 comprises athermoacoustic heat pump, a Stirling and/or a Brayton cycle heat pump,or a thermomagnetic heat pump.

In some embodiments, a thermoacoustic heat pump 18 is configured togenerate waves into a cooling fluid. Upon propagation through a thermalstack, the waves attenuate, and heat is transferred from one end of thethermal stack to the other end of the thermal stack. The heat pump 18comprises a loudspeaker 44 capable of varying (or cycling) the coolingfluid pressure. For example the loudspeaker 44 may includepiezo-electric material. The hot side 14 of the thermoelectric cooler 12is thermally coupled to the portion 24 of the conduit. For example, thedownhole tool may further comprise a heat exchanger 40. The heatexchanger 40 contacts the hot side 14 of the thermoelectric cooler 12and includes a porous passageway for the cooling fluid. The heatexchanger 40 is further thermally coupled to the thermal stack (notshown) extending in the conduit from the heat exchanger 40 towardanother heat exchanger (not shown) thermally coupled to the wellbore.

In some other embodiments, a Stirling and/or a Brayton cycle heat pump18 is configured to pump a compressible fluid back and forth between twochambers and compress or decompress the compressible fluid. Heat isdissipated from the compressed fluid into a heat exchanger (not shown)thermally coupled to the wellbore, and heat is absorbed by thedecompressed fluid from the heat exchanger 40.

In yet other embodiments, a thermomagnetic heat pump 18 is configured tocirculate a conductive fluid back and forth between the heat exchanger40 and the heat exchanger thermally coupled to the wellbore, across atleast one chamber containing a ferromagnetic material in a variablemagnetic field. The ferromagnetic material is cooled by removing themagnetic field. Some of the heat of the conductive fluid is absorbed bythe ferromagnetic material as the conductive fluid flows in thedirection toward the heat exchanger 40 across the chamber containing theferromagnetic material, thus cooling the conductive fluid. The coldconductive fluid is used to absorb heat from the heat exchanger 40 andfrom the thermoelectric cooler 12. Then, the ferromagnetic material isfurther heated by re-applying the magnetic field. Some of the heatgenerated in the ferromagnetic material is transferred from theferromagnetic material into the conductive fluid as the conductive fluidflows backward across the chamber containing the ferromagnetic materialin the direction toward the heat exchanger thermally coupled to thewellbore. The heat of the conductive fluid is then dissipated into thewellbore environment at the heat exchanger thermally coupled to thewellbore.

While the disclosure is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and description. It should be understood,however, that the drawings and detailed description thereto are notintended to limit the claims to the particular form disclosed, but onthe contrary, the intention is to cover all modifications, equivalents,and alternatives falling within the scope of the claims.

1. An apparatus for use in a downhole tool, comprising: a first thermoelectric cooler including a cold side and a hot side; and a heat pump including a conduit filled with a cooling fluid, wherein the heat pump is adapted for disposal within an elongated pressure housing of the downhole tool, and wherein the hot side of the first thermoelectric cooler is thermally coupled to a first portion of the conduit.
 2. The apparatus of claim 1, further comprising: a second thermoelectric cooler including a cold side and a hot side, wherein the hot side of the second thermoelectric cooler is thermally coupled to a second portion of the conduit.
 3. The apparatus of claim 1, wherein the heat pump includes a compressor and an expansion valve.
 4. The apparatus of claim 1, wherein the heat pump includes a compressor or a loudspeaker capable of varying a cooling fluid pressure.
 5. The apparatus of claim 4, further comprising: a thermally insulating housing including an opening, wherein the cold side of the first thermoelectric cooler is located inside the thermally insulating housing.
 6. The apparatus of claim 4, further comprising: a thermally insulating housing including an opening; and a thermally insulating support, wherein the thermally insulating support is inserted into the opening of the thermally insulating housing, and wherein the first thermoelectric cooler is partially embedded within the thermally insulating support.
 7. The apparatus of claim 1, further comprising: a thermally insulating housing including an opening; wherein the cold side of the first thermoelectric cooler is located inside the thermally insulating housing.
 8. The apparatus of claim 7, further comprising: a second thermoelectric cooler including a cold side and a hot side, wherein the cold side of the second thermoelectric cooler is located inside the thermally insulating housing, and wherein the hot side of the second thermoelectric cooler is thermally coupled to a second portion of the conduit.
 9. The apparatus of claim 8, wherein the thermally insulating housing includes a first compartment and a second compartment, wherein the cold side of the first thermoelectric cooler is located inside the first compartment, and wherein the cold side of the second thermoelectric cooler is located inside the second compartment.
 10. The apparatus of claim 7, further comprising: a second thermoelectric cooler including a cold side and a hot side; and a second thermally insulating housing, wherein the cold side of the second thermoelectric cooler is located inside the second thermally insulating housing, and wherein the hot side of the second thermoelectric cooler is thermally coupled to a second portion of the conduit.
 11. The apparatus of claim 7, further comprising: a heat exchanger including a passageway for the cooling fluid; a thermal conductor; and a thermally insulating support, wherein the heat exchanger contacts the hot side of the first thermoelectric cooler, wherein the thermal conductor contacts the cold side of the first thermoelectric cooler, and wherein the heat exchanger and the thermal conductor are partially embedded within the thermally insulating support.
 12. The apparatus of claim 11, wherein the thermally insulating support is inserted into the opening of the thermally insulating housing.
 13. The apparatus of claim 1, further comprising: a thermally insulating housing including an opening; and a thermally insulating support, wherein the thermally insulating support is inserted into the opening of the thermally insulating housing, and wherein the first thermoelectric cooler is partially embedded within the thermally insulating support.
 14. The apparatus of claim 13, further comprising: a second thermoelectric cooler including a cold side and a hot side, wherein the cold side of the second thermoelectric cooler is located inside the thermally insulating housing, and wherein the hot side of the second thermoelectric cooler is thermally coupled to a second portion of the conduit.
 15. The apparatus of claim 13, further comprising: a second thermoelectric cooler including a cold side and a hot side; and a second thermally insulating housing, wherein the cold side of the second thermoelectric cooler is located inside the second thermally insulating housing, and wherein the hot side of the second thermoelectric cooler is thermally coupled to a second portion of the conduit.
 16. The apparatus of claim 13, wherein the conduit further comprises a second portion located inside the thermally insulating housing.
 17. The apparatus of claim 16, wherein the thermally insulating housing includes a first compartment and a second compartment, wherein the cold side of the first thermoelectric cooler is located inside the first compartment, and wherein the second portion is located inside the second compartment.
 18. The apparatus of claim 13, further comprising: a second thermally insulating housing, wherein the conduit further comprises a second portion located inside the second thermally insulating housing.
 19. The apparatus of claim 13, wherein the cold side of the first thermoelectric cooler is located inside the thermally insulating housing.
 20. The apparatus of claim 13, further comprising: a heat exchanger including a passageway for the cooling fluid; and a thermal conductor, wherein the heat exchanger contacts the hot side of the first thermoelectric cooler, wherein the thermal conductor contacts the cold side of the first thermoelectric cooler, and wherein the heat exchanger and the thermal conductor are partially embedded within the thermally insulating support.
 21. The apparatus of claim 1, wherein the first thermoelectric cooler is adapted for thermal coupling to a component mounted on a chassis of the downhole tool.
 22. The apparatus of claim 16, wherein the first portion and the second portion of the conduit are assembled in series such that the cooling fluid leaving the heat pump circulates through the first portion and then through the second portion before reentering the heat pump.
 23. The apparatus of claim 1, wherein the first thermoelectric cooler is disposed tilted relative to a longitudinal axis of the elongated pressure housing. 